Expression Of High Mobility Group Box Chromosomal Protein 1 Research Articles

Netrin-1 Ameliorates Postoperative Delirium-Like Behavior in Aged Mice by Suppressing Neuroinflammation and Restoring Impaired Blood-Brain Barrier Permeability.

Postoperative delirium (POD) is a common and serious postoperative complication in elderly patients, and its underlying mechanism is elusive and without effective therapy at present. In recent years, the neuroinflammatory hypothesis has been developed in the pathogenesis of POD, in which the damaged blood-brain barrier (BBB) plays an important role. Netrin-1 (NTN-1), an axonal guidance molecule, has been reported to have strong inflammatory regulatory and neuroprotective effects. We applied NTN-1 (45 μg/kg) to aged mice using a POD model with a simple laparotomy to assess their systemic inflammation and neuroinflammation by detecting interleukin-6 (IL-6), interleukin-10 (IL-10), and high mobility group box chromosomal protein-1 (HMGB-1) levels. We also assessed the reactive states of microglia and the permeability of the BBB by detecting cell junction proteins and the leakage of dextran. We found that a single dose of NTN-1 prophylaxis decreased the expression of IL-6 and HMGB-1 and upregulated the expression of IL-10 in the peripheral blood, hippocampus, and prefrontal cortex. Nerin-1 reduced the activation of microglial cells in the hippocampus and prefrontal cortex and improved POD-like behavior. NTN-1 also attenuated the anesthesia/surgery-induced increase in BBB permeability by upregulating the expression of tight junction-associated proteins such as ZO-1, claudin-5, and occludin. These findings confirm the anti-inflammatory and BBB protective effects of NTN-1 in an inflammatory environment in vivo and provide better insights into the pathophysiology and potential treatment of POD.

HMGB-1/RAGE signaling inhibition by dioscin attenuates hippocampal neuron damage induced by oxygen-glucose deprivation/reperfusion.

Cerebral ischemia is one of the most common clinical diseases characterized by high morbidity and mortality. Neurocyte apoptosis and a cascade of inflammatory signals following cerebral ischemia-reperfusion injury (IRI) may contribute to secondary brain damage, resulting in severe neurological damage. It has been reported that dioscin, a natural steroid saponin, exerts anti-inflammatory properties against different diseases. The present study aimed to investigate the role of dioscin in oxygen-glucose deprivation/reperfusion (OGD/R) induction in hippocampal cells in vitro and in vivo. For the in vitro study, hippocampal cells were collected from rat embryos of gestational age of E18. The oxygen-glucose deprivation model in primary hippocampal neurons was used to mimic cerebral IRI in vitro. To select the optimum dioscin concentration and acting time, cell viability was evaluated by a Cell Counting Kit-8 (CCK-8) assay. Neurons subjected to OGD/R were treated with dioscin and the inflammatory cytokines, high mobility group box chromosomal protein 1 (HMGB-1)/receptor for advanced glycation end products (RAGE) signaling molecules and apoptosis-associated genes were determined. The intracellular reactive oxygen species (ROS) generation was detected. Furthermore, the effects of dioscin on the antioxidant defense mechanisms were evaluated by measuring the activity of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) and the glutathione (GSH)/glutathione disulphide (GSSG) ratio. In addition, OGD/R-induced cells were transfected with pcDNA3.1-HMGB-1 and treated with dioscin, and the neuronal cell apoptosis rate was determined using a terminal deoxynucleotidyl transferase-mediated 2-deoxyuridine 5-triphosphate-biotin nick-end labeling (TUNEL) assay. The mRNA and protein expression levels of the inflammatory factors were measured using real-time quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. For the in vivo investigation, the oxidation and anti-oxidation system in rat hippocampal tissue was evaluated by detecting the expression of the aforementioned oxidative stress-associated proteins, 3-NT as well as 8-oxo-deoxyguanosine (8-OHdG). In the hippocampal region, the apoptotic rate was determined using a TUNEL assay. The results demonstrated that dioscin at a dose of 400 ng/ml significantly reversed the increase in the expression levels of the inflammatory factors and attenuated those of apoptotic cytokines induced by OGD/R. Additionally, dioscin notably reversed the OGD/R-mediated activation of the HMGB-1/RAGE signaling pathway in vitro and in vivo. Cell treatment with dioscin significantly attenuated ROS production and increased the activity of antioxidant enzymes. Additionally, increasing the expression of HMGB-1 inhibited the protective effects of dioscin on cell apoptosis in the OGD/R-induced neurons. Furthermore, HMGB-1 overexpression reversed the antiapoptotic and anti-inflammatory effects of dioscin on neurons. The results of the present study indicated that dioscin exerted anti-inflammatory, antiapoptotic and antioxidant effects via the HMGB-1/RAGE signaling pathway. These results suggest a novel perspective of the protective effects of dioscin as a prospective remedial factor for IRI.

Association of chemokine expression in anterior cruciate ligament deficient knee with patient characteristics: Implications for post-traumatic osteoarthritis

BackgroundStromal cell-derived factor-1a (SDF-1α) and high mobility group box chromosomal protein 1 (HMGB1) are chemokines that can drive post-traumatic osteoarthritis (PTOA) induced by anterior cruciate ligament (ACL) injury. However, the influence of patient characteristics on expression of those chemokines remains unclear. Our aim was to determine the relationship between chemokine expression in synovial fluid (SF) of the ACL-deficient (ACL-D) knee and patient characteristics including time from injury, sex, and age. MethodsSF samples were collected immediately prior to the first-time ACL reconstruction (ACLR) from 82 patients. Expression of SDF-1α and HMGB1 was measured with human-specific solid phase sandwich enzyme-linked immunosorbent assays. The expression levels between groups divided by time from injury, or age, or sex was compared using Student's t-test. The association of SDF-1α or HMGB1 levels with those variables was determined using regression analysis and Pearson product–moment correlation coefficient. ResultsRegression and correlation analysis indicated significant correlation between SDF-1α expression and time from injury in the cohort (r = −0.266, P = 0.016, n = 82) and in females (r = −0.386, P = 0.024, n = 34). Significant correlation was also observed between SDF-1α expression and age in the cohort (r = −0.224, P = 0.043, n = 82) and in males (r = −0.289, P = 0.046, n = 48). No significant correlation between HMGB1 expression and patient characteristics was detected. ConclusionsSDF-1α rather than HMGB1 might serve as a protein marker for monitoring the development of PTOA in the ACL-D knee, especially in female patients.

Uric Acid Induces Endothelial Dysfunction by Activating the HMGB1/RAGE Signaling Pathway.

Uric acid (UA) is a risk factor for endothelial dysfunction, a process in which inflammation may play an important role. UA increases high mobility group box chromosomal protein 1 (HMGB1) expression and extracellular release in endothelial cells. HMGB1 is an inflammatory cytokine that interacts with the receptor for advanced glycation end products (RAGE), inducing an oxidative stress and inflammatory response, which leads to endothelial dysfunction. In this study, human umbilical vein endothelial cells (HUVECs) were incubated with a high concentration of UA (20 mg/dL) after which endothelial function and the expression of HMGB1, RAGE, nuclear factor kappa B (NF-κB), inflammatory cytokines, and adhesion molecules were evaluated. UA inhibited endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production in HUVECs, increased intracellular HMGB1 expression and extracellular HMGB1 secretion, and upregulated RAGE expression. UA also activated NF-κB and increased the level of inflammatory cytokines. Blocking RAGE significantly suppressed the upregulation of RAGE and HMGB1 and prevented the increase in DNA binding activity of NF-κB and the levels of inflammatory cytokines. It also blocked the decrease in eNOS expression and NO production induced by UA. Our results suggest that high concentrations of UA cause endothelial dysfunction via the HMGB1/RAGE signaling pathway.

IL-1β mediating high mobility group box protein-1 expression in condylar chondrocyte during temporomandibular joint inflammation.

Temporomandibular joint (TMJ) osteoarthritis(OA)characterized with cartilage degen-eration is associated with inflammation. High mobility group box chromosomal protein-1(HMGB-1)is a potent mediator of inflammation and the trigger of OA. The expression of HMGB-1 in TMJ OA was uncovered, but the role of HMGB-1 in TMJ cartilage degeneration is not fully understood. In this study, the regulation of HMGB-1 in TMJ condylar cartilage was revealed. A complete Freund's adjuvant (CFA)-induced TMJ inflammation animal model was employed and the expression of HMGB-1 was detected at 1st, 2nd, and 6th weeks by immunohistochemistry. TMJ condylar chondrocytes were incubated with IL-1β (10 and 40 ng/ml) at 24, 48, and 72 h, and the translocation and protein level of HMGB-1 were evaluated by immunofluorescence and Western blot. Nuclear HMGB-1 staining was predominantly located in chondrocytes of both the fibrosis and proliferative zones in healthy TMJ. 1st week and 2nd week after CFA injection, immunoreaction could be detected in the cytoplasms of HMGB-1-positive cells and cartilage matrix especially in hypertrophic zone. At 6th week after CFA injection, cartilage matrix expression was disappeared and the cytoplasm expression of HMGB-1 was very weak in hypertrophic zone. HMGB-1 was translocated from the nucleus to the cytoplasm at 48 h after incubated with IL-1β (10 ng/ml and 40 ng/ml). The protein level of HMGB-1 was increased after stimulation and had a peak at 48 h. HMGB-1 might be associated with TMJ inflammation and OA. Insight into the role of HMGB-1 in TMJ inflammation is helpful to add the new knowledge into the pathogenesis of TMJ OA.

Autophagy induction contributes to the resistance to methotrexate treatment in rheumatoid arthritis fibroblast-like synovial cells through high mobility group box chromosomal protein 1

BackgroundRheumatoid arthritis fibroblast-like synovial cells (RA-FLS) show resistance to methotrexate (MTX) treatment. To better understand the mechanisms of this resistance, RA-FLS and osteoarthritis fibroblast-like synovial cells (OA-FLS) were isolated and exposed to MTX. We analyzed the autophagy induced by MTX in vitro and its relationship to apoptosis.MethodsCell viability was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and apoptosis was detected by flow cytometry and Western blot analysis. Autophagy was determined by transmission electron microscopy as well as Western blot analysis. The expression levels of Beclin-1, LC3, Akt, p-Akt, mammalian target of rapamycin (mTOR), p-mTOR, high mobility group box chromosomal protein 1 (HMGB1), and an 85 kDa caspase cleaved fragment of poly(ADP-ribose) polymerase were measured by Western blotting.ResultsMTX-induced apoptosis was increased in OA-FLS compared with RA-FLS. However, MTX stimulated the autophagy response in RA-FLS by inducing autophagosome formation, but not in OA-FLS. In RA-FLS, transfection with Beclin-1 small interfering RNA inhibited autophagy and increased susceptibility to MTX, which induces cell death. MTX upregulated autophagy through its ability to enhance the expression of HMGB1 and Beclin-1 rather than through the Akt/mTOR pathway.ConclusionsAutophagy induction contributes to resistance to MTX treatment in fibroblasts from patients with rheumatoid arthritis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-015-0892-y) contains supplementary material, which is available to authorized users.

Expression and purification of functional HMGB1 A box by fusion with SUMO.

High-mobility-group-box chromosomal protein 1 (HMGB1) is a ubiquitous and abundant nuclear protein in eukaryotic cells. Nuclear HMGB1 serves an important role in maintaining nuclear stability under stress. However, extracellular HMGB1 exerts actions, which are distinctly different compared with these intracellular functions. HMGB1, when released extracellularly, is a potent innate signal, which initiates host defense mechanisms or tissue regeneration. HMGB1 has two DNA-binding domains: HMG A box and B box. The HMGB1 A box exhibits an antagonistic, anti-inflammatory effect, and is a potential therapeutic target, however, the large-scale expression and purification of the HMGB1 A box with high efficiency remains to be reported. In the present study, a SUMO-fusion expression system was used to express and purify high levels of functional HMGB1 A box to meet the requirements of therapeutic protein production.

Induction of cytokine production in cholesteatoma keratinocytes by extracellular high-mobility group box chromosomal protein 1 combined with DNA released by apoptotic cholesteatoma keratinocytes.

High-mobility group box chromosomal protein 1 (HMGB-1), a nuclear DNA binding protein, was recently rediscovered as a new proinflammatory cytokine. The purpose of this study was to determine HMGB-1 expression in vivo and to identify the effect of extracellular HMGB-1 in inflammatory process associated with bone destruction in cholesteatoma. We investigated the expression and location of HMGB-1 in the cholesteatoma and healthy skin using an immunofluorescence assay. We also detected apoptosis and DNA fragments in the cholesteatoma by TUNEL staining. HMGB-1 concentration in apoptotic supernatants from UV light-treated cells, culture supernatants and its translocation in cholesteatoma keratinocytes stimulated by supernatants from UV light-treated cells were measured by immunoblot analysis and immunofluorescence assay. Cultures of human cholesteatoma keratinocytes were exposed to CpG-DNA, HMGB-1, or CpG-DNA complexed to HMGB-1 for 24 h. Cytokines in the culture supernatant were measured by ELISA. In addition, levels of proinflammatory cytokines released by cholesteatoma keratinocytes stimulated by supernatants from UV light-treated cells with or without anti-HMGB-1 antibodies and supernatants from UV light-treated cells with DNase 1 were measured by enzyme-linked immunosorbent assay. The expression of HMGB-1 in cholesteatoma increased and it translocated both to the cytoplasm and extracellular space. Furthermore, the HMGB-1 concentration in supernatants increased significantly after addition of supernatants from UV light-treated cells. TNF-α and IL-1β can be induced by purified HMGB-1 combined with CpG-DNA in the cholesteatoma keratinocytes. In addition, supernatants of apoptotic cells containing HMGB-1-DNA were effective in inducing TNF-α and IL-1β secretion. This study suggested that persistent expression of extracellular HMGB-1 and DNA fragments in cholesteatoma leads to TNF-α and IL-1β production, causing bone resorption and destruction. Thus, we have implicated that HMGB-1-DNA complexes might act as a key molecule involved in bone resorption associated with cholesteatoma.

High mobility group box 1 release from cholangiocytes in patients with acute-on-chronic liver failure.

High mobility group box chromosomal protein 1 (HMGB1) is an important proinflammatory molecule in a number of inflammatory disorders, but little is known about its role in acute-on-chronic liver failure (ACLF). To elucidate the role of HMGB1 in ACLF, the expression of HMGB1 in liver specimens from patients with ACLF was investigated. Immunohistochemical staining was performed to confirm the expression and subcellular localization of HMGB1 in liver specimens obtained from 13 patients with ACLF caused by hepatitis B virus (HBV) infection, 20 patients with chronic viral hepatitis B and 20 healthy controls. In addition, TFK-1 cells (human cholangiocarcinoma cell line) were stimulated with lipopolysaccharide (LPS) or tumor necrosis factor (TNF)-α. The extracellular level of HMGB1 in the culture medium was then determined by ELISA, and cell viability was also examined. In patients with ACLF caused by HBV infection, HMGB1 was found mainly in the cholangiocytes, and cytoplasmic translocation was observed in the cholangiocytes in the liver specimens. In the TFK-1 cell cultures, HMGB1 levels gradually increased from as early as 4 h after stimulation with LPS or TNF-α until the end of the stimulation. LPS and TNF-α actively induced the cytoplasmic translocation of the HMGB1 protein in TFK-1 cells. These data suggest that HMGB1 plays a critical role in the systemic inflammation associated with ACLF.

(Pro)renin receptor blocker improves survival of rats with sepsis

BackgroundThe renin-angiotensin system (RAS) affects inflammatory responses during sepsis. Nonproteolytic activation of prorenin by the (pro)renin receptor has recently been shown to stimulate the tissue RAS. In the present study, the effect of (pro)renin receptor blocker (PRRB) pretreatment on sepsis in a rat cecal ligation and puncture (CLP) model was investigated. Materials and methodsMale Sprague-Dawley rats underwent CLP and were randomly divided into two groups: PRRB-treated group and control peptide–treated group. Survival was analyzed for 7 d after CLP. The serum concentrations of cytokines and high-mobility group box chromosomal protein 1 (HMGB1) were measured at three time points (0, 3, and 6 h after CLP). Hematoxylin-eosin staining and immunohistochemical staining for nonproteolytically activated prorenin and HMGB1 were performed on the cecum to assess pathologic changes found 6 h after CLP. ResultsTreatment with PRRB improved the survival rate of the post-CLP septic rats (P = 0.023). PRRB also significantly reduced serum tumor necrosis factor-α, interleukin-1β, and HMGB1 levels 6 h after CLP. In CLP rats that were treated with control peptide, the expression of activated prorenin was elevated in peritoneal foam cells. Moreover, expression of HMGB1 was increased in peritoneal inflammatory cells. In contrast, both were markedly suppressed in CLP rats that were treated with PRRB. ConclusionsPRRB significantly improved the survival rate of rats with clinically relevant sepsis, possibly by attenuating a sepsis-induced systemic inflammatory response. We propose that overactivation of the RAS by activation of prorenin in foam cells may be a significant contributor to sepsis.

IL‐1β/HMGB1 Complexes Promote The PGE2 Biosynthesis Pathway in Synovial Fibroblasts

PGE2 is a potent lipid mediator of pain and oedema found elevated in RA. Microsomal prostaglandin E synthase-1 (mPGES-1) is a terminal enzyme of the PGE2 pathway inducible by proinflammatory cytokines. mPGES-1 is markedly upregulated in RA synovial tissue despite antirheumatic treatments, suggesting that multiple inflammatory stimuli contribute to its induction. High-mobility group box chromosomal protein 1 (HMGB1) is known to induce inflammation both by direct interaction with TLR4 and by enhancement of other proinflammatory molecules signalling, through complex formation. The high expression of extracellular HMGB1 within the inflamed synovium, implies its pro-arthritogenic role in RA. We aimed to investigate the effects of IL-1β/HMGB1 complexes on mPGES-1 and other enzymes of the PGE2 pathway in synovial fibroblasts (SFs) from patients with arthritis. Furthermore, we studied the effect of COX-2 inhibition and IL-1RI antagonism on prostanoid and cytokine production by SFs. Stimulation of SFs with HMGB1 in complex with suboptimal amounts of IL-1β significantly increased mPGES-1 and COX-2 expressions as well as PGE2 production, as compared to treatment with HMGB1 or IL-1β alone. Furthermore, NS-398 reduced the production of IL-6 and IL-8, thus indicating that IL-1β/HMGB1 complexes modulate cytokine production in part through prostanoid synthesis. Treatment with IL-1RA completely abolished the induced PGE2 and cytokine production, suggesting an effect mediated through IL-1RI. IL-1β/HMGB1 complexes promote the induction of mPGES-1, COX-2 and PGE2 in SF. The amplification of the PGE2 biosynthesis pathway by HMGB1 might constitute an important pathogenic mechanism perpetuating inflammatory and destructive activities in rheumatoid arthritis.

The role of high mobility group box chromosomal protein 1 in rheumatoid arthritis

High mobility group box chromosomal protein 1 (HMGB1) is a ubiquitous highly conserved single polypeptide in all mammal eukaryotic cells. HMGB1 exists mainly within the nucleus and acts as a DNA chaperone. When passively released from necrotic cells or actively secreted into the extracellular milieu in response to appropriate signal stimulation, HMGB1 binds to related cell signal transduction receptors, such as RAGE, TLR2, TLR4 and TLR9, and becomes a proinflammatory cytokine that participates in the development and progression of many diseases, such as arthritis, acute lung injury, graft rejection immune response, ischaemia reperfusion injury and autoimmune liver damage. Only a small amount of HMGB1 release occurs during apoptosis, which undergoes oxidative modification on Cys106 and delivers tolerogenic signals to suppress immune activity. This review focuses on the important role of HMGB1 in the pathogenesis of RA, mainly manifested as the aberrant expression of HMGB1 in the serum, SF and synovial tissues; overexpression of signal transduction receptors; abnormal regulation of osteoclastogenesis and bone remodelling leading to the destruction of cartilage and bones. Intervention with HMGB1 may ameliorate the pathogenic conditions and attenuate disease progression of RA. Therefore administration of an HMGB1 inhibitor may represent a promising clinical approach for the treatment of RA.

High mobility group box chromosomal protein 1 in acute-on-chronic liver failure patients and mice with ConA-induced acute liver injury

High mobility group box chromosomal protein 1 (HMGB1) is an important proinflammatory molecule in many inflammatory disorders, but little is known about its role in acute-on-chronic liver failure (ACLF). Here, we investigated the relationship between the expression of HMGB1 and the disease onset and severity of ACLF patients and mice with acute liver injury/failure induced by concanavalin A (ConA). Peripheral blood mononuclear cells (PBMCs) and serum from ACLF patients were collected, and a mouse model of acute liver injury/failure was induced by ConA. HMGB1 mRNA expression in patient PBMCs or in murine livers and serum HMGB1 protein in ACLF patients and mice were assayed by RT-PCR and Western blotting, respectively. HMGB1 translocation in hepatocytes of ConA-treated mice was assessed by immunohistochemical staining. Up-regulated HMGB1 mRNA levels in PBMCs and accumulated protein in serum were both correlated with disease severity in ACLF patients. In the animal model, HMGB1 levels increased at 4h and reached its peak value at 8–12h after challenge with ConA, which suggests that HMGB1 is a relatively late proinflammatory cytokine compared with TNF-α. Translocation of HMGB1 from the nucleus to the cytoplasm in hepatocytes was correlated with the severity of liver injury in mice. While specific anti-HMGB1 antibodies and nicotine protected mice from acute liver injury/failure by reducing mortality and improving liver tissue injury, treatment with recombinant HMGB1 led to an increased mortality due to ConA challenge. Thus, the data from the present study suggest that HMGB1 plays a critical role in the systemic inflammation of ACLF and could be a potential therapeutic target in the treatment of ACLF.

The role of HMGB1 in ischemia-reperfusion injury in the rat small intestine

DOI of original article: 10.1016/j.jss.2012.0 * Corresponding author. Uniformed Services MD 20814, USA. Tel.: þ1 301 295 2552; fax: þ E-mail address: hassan_tetteh@hks09.ha 0022-4804/$ e see front matter a 2013 Elsev doi:10.1016/j.jss.2012.04.004 Kojima et al. highlight the High Mobility Group Box Chromosomal Protein 1 (HMGB1) and its potential role in response to ischemia-reperfusion injury in the small intestine [1]. Their results suggest that HMGB1 is an importantmediator in the rat model of ischemia-reperfusion injury, and that therapeutic agents may be developed for targeted therapy in ischemiarelated injury to the small intestine. Several studies have previously explored the impact and role ofHMGB1 inacute lung injuryand ischemia-reperfusion injuryof the kidney, heart, brain, and liver [2e5]. This current studyby the authors appears to be the first report that investigates HMGB1 in the intestinal rat model of ischemia-reperfusion injury, and it offers three unique perspectives that may create opportunity for further investigation and innovation in the treatment of ischemia-reperfusion injury. First, the study demonstrated that increased serum HMGB1 concentration and its localization in damaged intestinal tissue were identified after reperfusion injury. Second, the study suggests that there is strong expression of HMGB1 in the damaged cells of terminal protein of the villi of small intestine. Finally, the administration of anti-HMGB1 antibody appears to ameliorate local disturbances and improve survival in the study subjects over controls. The authors’

Expression of high mobility group box chromosomal protein 1 in mice with lupus nephritis

To determine the role of the novel proinflammatory cytokine high mobility group box chromosomal protein 1 (HMGB-1) in the pathogenesis of lupus nephritis. Serum levels of anti-dsDNA antibodies were determined by enzyme linked immunosorbent assay (ELISA). Renal morphologic features were examined by light microscopy, electron microscopy, and immunohistologic analyses. The mRNA expression of HMGB-1 and monocyte chemoattractant protein-1 (MCP-1) was detected by RT-PCR. MRL/lpr mice demonstrated characteristic alterations of serum immune parameters, with progressively increased anti-dsDNA antibodies with age, compared with age-matched C57BL/6J mice. MRL/lpr mice showed progressive development of renal damage, starting at 12 weeks of age and reached the peak at 20 weeks. The observed lesions included the presence of enlarged hypercellular glomeruli, with increased numbers of both resident cells and infiltrating leukocytes. Higher expression of HMGB-1 mRNA was found in MRL/lpr mice than what in C57BL/6J mice. Expression of HMGB-1 was positively correlated with that of MCP-1 mRNA. The results demonstrate that the higher expression of HMGB-1 may contribute to the pathogenesis of lupus nephritis.

Effect of qinghuobaiduyin on the expression of high mobility group box chromosomal protein 1 in macrophage

To observe the expression of high mobility group box chromosomal protein 1(HMGB1) in RAW264.7 macrophages after interfering with burning serum and qinghuobaidu-yin (QHBDY), and to find out the endogenous protection mechanism of QHBDY resisting inflammation reaction. RT-PCR was used to detect the expression of HMGB1 in RAW264.7 macrophages after interfering RAW264.7 macrophages with normal SD rat serum, burning SD rat serum, and QHBDY feeding SD rat serum. Small quantity of HMGB1 mRNA was expressed in RAW264.7. The expression of HMGB1 mRNA fluctuated around the standard level after interfering with normal serum of SD rats. The expression of HMGB1 mRNA rose at 3 h, and then decreased to the standard level; at 18 h, it rose rapidly; at 36 h, it reached the peak; and at 48 h, it remained at the high level after interfering with burning serum. The expression of HMGB1 mRNA increased at 3 h, and then decreased to the standard level. At 24 h, it started to rise after interfering with herb serum, and was lower than that of; the burning serum group (P<0.05). Burning serum can increase the expression of HMGB1 mRNA in RAW264.7. QHBDY can decrease the high expression of HMGB1 mRNA in RAW264.7 caused by burning serum.

The Vagus Nerve and Nicotinic Receptors Involve Inhibition of HMGB1 Release and Early Pro-inflammatory Cytokines Function in Collagen-Induced Arthritis

The cholinergic anti-inflammatory pathway, a vagus nerve-dependent mechanism, inhibits cytokine releases in models of acute inflammatory disease. We investigated the efficacy and elucidated the possible mechanism of the cholinergic anti-inflammatory pathway on collagen-induced arthritis (CIA) in mice. Fifty-six male DBA/1 mice were divided into four groups: control mice (sham vagotomy + phosphate-buffered saline; shamVGX+PBS), model mice (shamVGX+PBS+CIA), vagotomy mice (VGX+PBS+CIA), and nicotine (Nic) mice (shamVGX+Nic+CIA). We subjected mice to left-side cervical vagotomy 4 days before induction of arthritis. Mice in the nicotine group were injected with nicotine (250 microg/kg per day) 4 days before arthritis induction. Arthritis score was measured and histopathologic assessment of joint sections carried out. The concentration of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-10 in serum were evaluated by ELISA. Expression of high-mobility group box chromosomal protein 1(HMGB1) was evaluated by immunohistochemical staining of joints. Vagotomy exaggerated, whereas nicotine attenuated, clinical arthritis. Histopathologic findings confirmed that nicotine reduced infiltration of inflammatory cell and bone destruction. Expression of TNF-alpha and IL-6 decreased in nicotine-pretreated mice compared with model and vagotomy mice; IL-10 levels were not significantly different between the model group and nicotine group. Nicotine reduced the expression and translocation of HMGB1 in the inflamed joints of CIA mice. The cholinergic anti-inflammatory pathway has an anti-inflammatory role in the pathophysiology of rheumatoid arthritis (RA) via inhibiting HMGB1 release and early pro-inflammatory cytokines function. Study of this pathway could be used for RA therapy.

Role of high mobility group box chromosomal protein 1 in pathogenesis of ulcerative colitis in mice

Objective To establish ulcerative colitis （UC） model in BALB/c mice and to investi- gate the role of high mobility group box chromosomal protein 1 （ HMGB1 ） in pathogenesis of UC. Methods Thirty-two BALB/c mice were randomly divided into UC group （n =24, which were fed with 3% dextran sulfate sodium solution） and control group （n = 8, which were fed with water）. The animals were sacrificed at 24, 96 and 168 hours, respectively, to collect samples of colon and blood. The serum level of HMGB1 was measured with ELISA and the expression of HMGB1 in colon was determined by Western blotting analysis. Results Histological scoring increased with the induction of the model, and manifestation of colon mu- cosa at 168h was similar with that of UC in human. The serum level of HMGB1 was slightly higer at 24 h than that of control （5.09 ± 0. 61 μg/L vs 4.49 ± 0. 53 μg/L, P 〉 0. 05 ）, and reached a peak at 96 h （14.74 ± 0.60 μg/L, P〈0. O1）, decreased at 168 h （9.03 ± 0.78 μg/L, P〈0.01）. The expression of HMGB1 in colon was slightly increased at 24h than that of control （ 0. 56 ± 0.02 vs O. 49 ± 0. 03, P 〉 0. 05） , significantly increased at 96h （0. 76 ±0. 03, P 〈0. 05） and at 168 h （0. 77 ±0. 04, P 〈0. 05）. Conclusion HMGB1 might be involved in pathologic changes of UC at a later stage. Key words: Colitis, ulcerative; High mobility group box chromosomal protein 1; Mice; Sodium dextran sulfate

Pivotal Advance: HMGB1 expression in active lesions of human and experimental multiple sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating disease of the CNS, most frequently starting with a series of bouts, each followed by complete remission and then a secondary, progressive phase during which the neurological deficit increases steadily. The underlying molecular mechanisms responsible for disease progression are still unclear. Herein, we demonstrate that high mobility group box chromosomal protein 1 (HMGB1), a DNA-binding protein with proinflammatory properties, is evident in active lesions of MS and experimental autoimmune encephalomyelitis (EAE) and that HMGB1 levels correlate with active inflammation. Furthermore, the expression of the innate HMGB1 receptors--receptor for advanced glycation end products, TLR2, and TLR4--was also highly increased in MS and rodent EAE. Additionally, in vitro activation of rodent CNS-derived microglia and bone marrow-derived macrophages demonstrated that microglia were equally as capable as macrophages of translocating HMGB1 following LPS/IFN-gamma stimulation. Significant expression of HMGB1 and its receptors on accumulating activated macrophages and resident microglia may thus provide a positive feedback loop that amplifies the inflammatory response during MS and EAE pathogenesis.

Systemic TNF blockade does not modulate synovial expression of the pro-inflammatory mediator HMGB1 in rheumatoid arthritis patients – a prospective clinical study

IntroductionHigh-mobility group box chromosomal protein 1 (HMGB1) has recently been identified as an endogenous mediator of arthritis. TNF and IL-1β, pivotal cytokines in arthritis pathogenesis, both have the ability to induce the release of HMGB1 from myeloid and dendritic cells. It was, therefore, decided to investigate whether treatment based on TNF blockade in rheumatoid arthritis (RA) affects the expression of synovial HMGB1.MethodsRepeated arthroscopy-guided sampling of synovial tissue was performed in nine patients with RA before and nine weeks after initiation of anti-TNF mAb (infliximab) therapy. Synovial biopsy specimens were analysed for HMGB1 protein by immunohistochemical staining and for HMGB1 mRNA expression by real-time reverse transcriptase PCR (RT-PCR). Statistical evaluations were based on Wilcoxon's signed rank tests or Spearman rank sum tests.ResultsAberrant, extranuclear HMGB1 and constitutive nuclear HMGB1 expression, with histological signs of inflammation, were evident in all biopsies obtained before infliximab therapy. Signs of inflammation were still evident in the second biopsies obtained nine weeks after initiation of infliximab therapy. The cytoplasmic and extracellular expression of HMGB1 decreased in five patients, remained unchanged in one patient and increased in three patients, making the overall change in HMGB1 protein expression not significant. No correlation between the clinical response, as measured by disease activity score calculated for 28 joints (DAS28) or the American College of Rheumatology response criteria (ACR 20, 50, and 70), and the direction of change of HMGB1 expression in individual patients could be discerned. In addition, infliximab therapy did not alter HMGB1 mRNA synthesis.ConclusionPro-inflammatory HMGB1 expression during rheumatoid synovitis was not consistently influenced by TNF-blocking therapy with infliximab. This suggests that TNF is not the main inducer of extranuclear HMGB1 during synovitis and that HMGB1 may represent a TNF-independent molecule that could be considered as a possible target for future therapeutic intervention in RA.